If a is an array of 5 integers then which of the following is the correct way to increase its size to 10 elements?

Question:If a is an array of 5 integers then which of the following is the correct way to increase its size to 10 elements?

1.int[] a = new int[5]; int[] a = new int[10];

2.int[] a = int[5]; int[] a = int[10];

3.int[] a = new int[5]; a.Length = 10 ;

4.int[] a = new int[5]; a = new int[10];

Answer:4